The present invention relates to a power-driven portable machine such as chain saw and, more particularly, to a power-driven portable machine which requires an observation of state of operation of the machine.
Hitherto, the evaluation or judgement of the condition or state of operation of power-driven portable machine such as chain saw has been made relying upon the knowledge and experience of the operator. However, in order to fully enjoy the performance of the machine while making most of the operator's ability and ensuring the safety of the work, it is desirable that the condition or state of operation such as revolution speed of the motor or internal combustion engine, amount of remaining fuel, lubricating condition or the like is observed continuously.
To cope with this demand, Japanese patent application No. 157,384/1977 proposes a power-driven portable machine having displaying means for permitting continuous observation of operating condition.